Pathogen Reduction Crediting for Reverse Osmosis: Getting Credit where Credit is Due with Good Surrogates

Abstract

Key Takeaways

• Reverse osmosis (RO) is an excellent barrier against pathogens (e.g., 6-log₁₀ virus reduction), but is under-credited for pathogen reduction due to the lack of good surrogates.
• Conductivity and total organic carbon, the most common surrogates, only provide log reduction credits of 1.5 to 2 log₁₀. Other naturally occurring ions provide opportunity to increase RO credits up to 3-log₁₀ .
• Alternative approaches—such as the use of spiked surrogates—have the potential to provide 4- or 5-log₁₀, but more research is needed for implementation.
• This issue shows practitioners and regulators how to extend RO crediting with existing surrogates and points to the need for further research to maximize RO’s full potential.